Aeroplane



Oct. 11, 1938. w. w. ROTHENHOEFER 2,133,043

EROPIJANE Filed Aug. 19, '1935 4 Sheets-Sheet 1 Oct. 11, 1938- w. w. RoTHENHoEi-'ER v 2,133,043-

AEROPLANE Filed Aug. 19, 1935 4 sheets-sheets a* g :r- 4: v| l l I l* f 44 il. Zd,

@WMMP Patented Oct. 11,1938v welter Avv.. lrotllenlloea' l,v st'. lool., Mo. lllppllootlon August 19,- 1935, vserlol No. :am

` 'scam 4(cl. ul-17)" My invention relatesto improvements in aeroplanes andthe main object is to provide an improved.' supporting and sustaining means for aeroplanes of the general type known as helicopters and designed to permit vertical ascent and descent.

Another object isfto provide in a helicopter type supporting means a rotor having elongated blades'and means for increasing the lift or ver- 10 tical thrust of these blades during any part of their rotation or orbitalmovement 'wherebythe aeroplane may be tilted forwardly, rearwardly or laterally to guide the aeroplane in' horizontal flight. Another lobject'is to provide a helicopter type supporting means comprising a rotormad'e up' of aplurality o f-elongated airfoils or winglikeblades and` means at the outer ends thereof for varying the cross sectional shape o'r area of the blades at periodic intervals during their. orbital motion and any points around the circumference. thereof whereby the lift' will be periodically in creased t'o guide and `control the ight of the,

aeroplane.

'25' Another object is to provide novel and positivel meansfor controlling-boththe degree and the .horizontal position of the aforesaid increased lift ofthe blades. l i With'th'ese and other objects in view the invention resides in the novel construction and arrangement of parts as hereinafter fully set forth and claimed, referencebeing had to thev accompanying drawings wherein:

Figure 1 is a side elevation of an aeroplane constructed in `accordance with' my invention.

FigureZis a plan view. Figure 3 is anenlarged cross' section through the fuselage and rotorof the aeroplane s hown -Figure 4 is a; horizontal section through the vrotor along the line 4--4 in Figure 3.

Figuret is a section along the line 5-5 -in Figure 3. v

Figure 6 is Van lenlargedfperspective view'of one of the cam pluri-gers alone.

o Figure 7 is a section-alongv the line 1 -1 in mgul'e 3. i j

Figure 8 is an enlarged longitudinal section through the outer end portion of one rotor blade showing the'adjustable member as adjusted to1 increase the liftof the blade. Figure 9 isan inverted plan Vview of 'the strucf 4v ture shown in Figure 8.

Figure 10 is a cross section along the 1111 .I0-I0 in Figure 8.

-'Figure 11 is an inverted plan' viewusimilar to Figure 9 but showing a Imodifiedforlnof lift adjusting member.

Figure 12 is a cross section through .the outer end portion'of the blade shown in Figure 11. 5 Figure 13 is an enlarged section along the line Il-' in' Figure 3 showing one rotor blade tilted upward at its leading edge.-

Figure 14 is a similar view showing the position of the parts when the rotor bladevis tilted .up- 10 ward at its trailing edge.

Referring now with more particularity to the drawings my invention comprises a rotondesignated 'generally at Il mounted abovethefuse lage lIl of the aeroplane or substantially the 15 center of gravity of the structure. ,The rotor comprises a'hubjdrum ,I2 secured at Il atop a drive shaft Il 'whi'eh extends vertically up through the upper surface I5 of the fuselage and is :driven by a conventional vengine Elo- 20 cated in any suitable position; As herein shown the engine' E is of `the air cooled radial type placed in theA nose oi' 'the fuselage Il and connected to the drive shaft I4 throughs propeller shaft .IQ and gears I'l. A clutch (not shown) 2&5

- of any suitable kind may be used theshaft l6.' Some distance below the drum I2 the drive 'i shaft u is supported and ,ioumaled through .a bearing block I8 which is rigidly mounted above the fuselage il by a streamlined turret I i as 30 shown. Also at the pointwhere the drive'shaft- Il enters the upper fuselage surface II the shaft is placedthrough al thrustbearing 2l secured at 2| to the fuselage.

The hu'b drum l2 has an annular upstanding 35 wall 22 turnedl inward to form an annular mounting flange 234 at its .upper end and. a

circular mounting plate 241s screwed at 25'. to

`this:ilang`e23. 4Four rotor blades or wings 26, 2id., Ziband 2te, 40 are provided and are -of any suitable length v land chordfand are fabricated similar tothe' .usual wing structure of aeroplanes with a framework 21 and covering 28.- At their predetermined inner ends the blades are securedto elongated 45 leaf springs 2l, 29a, 2lb and 29e each made up of several leaves and formed at their inner ends with bearing balls 3L 2 These blades 26, 26a, 26h and 20c are arranged 'with theirmounting springs`29, 29a, 28h and 29c 50 4in crossing overlapping arrangement latop the mounting'plate 2l as shown in Figure 4 4andarel rnounted'irl Vsuch position by four b earing blocks 3|` secured at 32 to the mounting plate 2l and having rounded-sockets Il receiving the-bearing balls at the ends of the springs. 'I'he blades thus .extend radially but eccentrieally from the rotor I0, that is each opposed pair of blades are axially parallel but not in exact alignment even though the structure as a whole is nicely balanced as will be understood. 'I'hrough the ball mounting of their inner ends the blades may swing upwardly and downwardly at their free ends and may also twist or turn on their axes. Adjacent the point where each spring 29, 29a, 29h and 29e extends from the rotor IIl inverted U- shaped brackets or shackles 34 are set astraddle the springs and secured at 35 te the mounting plate 24 to limit the aforesaid upward and downward swinging c-f the blades at their free ends. Rocker plates 36 are secured on the upper and lower faces of the springs where they pass through the brackets 34 and viewed from the ends these .e resiliently urged upward against the bights 43 of the brackets 34' and dueto the shape of the angular faces 38 of the rocker plates 36 the blades will stand not in a true horizontal plane but at an angle to the horizontal so that the blades will tilt upwardly either at their intended leading edges 44 or their trailing edges 45 as shown in Figures 13 and 14. At the same time the blades may swing upward or downward within limits at the free ends as described due to the resiliency of the springs 29, 29a, 29h and 29c and oi': their mounting through the brackets 34'.

The structure as so far recited is completein that rotation of the blades 26, 26a, 26h and 25e is calculated to raise and lsustain the aeroplane in flight. Tl'ae normal direction of rotation for this purpose is indicated by the several arrows in the drawings and of course the leading edges 44 of the blades move forwardly around the cr-` bital path of the blades. During tl-ds rotation the air pressure on the blades tends tcrock them back on their axes so that the said leading edges 44 are tilted upwardly (Figure 13). Now should the engine E fail the pilot may disengage the rotor from the engine allowing the rotor to turn free. The natural result of the falling of the plane thus `brought about is to reverse the direction of rotation of the rotor blades 26, 26a, 26h and 26e and the air pressure thus being reversed on the blades rocks them back so that their trailing edges 445 are inclined upwardly and now an upward thrustv is-again previded bythe blades tending to lower the `aeroplane slowly and safely to the ground. This is the -purpose and function of the rocker supports for the blades in the brackets 3.

To guide the aeroplane in horizontal flight I provide means for varying the lift or upward thrust of the blades 26, 26a, 26h and 26o during any part of their orbital path or movemeet as will now be described.

As shown in Figures 8, and 10 substantially triangular exible and resilient aps or leaves 46 are secured to the undersides of the blades 26, 26a, 26h and 26o adjacent the-trailing edges and cuter ends thereof. These leaves 46 are-preferably made of some at spring metal and are secured by screws or rivets 41 to the framework 21 of the blades leaving the trailing edges 4'8 and inner edges 49 ef the leaves free. Normally the leaves then lie flat beneath the blades to offer no obstruction to the air. Bell crank pressure levers 5I) are fulcrumed at 5| within the outer ends of the blades and have pressure feet 52 which bear on the free corners of the leaves 46 but which are normally held upward by retractile coil'springs 53 stretched between the pull arms 54 of the levers 50 and screw eyes 55 affixed within the wings as shown. Operating cables 56 are secured to these pull arms 54 and extend inward longitudinally through the blades through bearing sleeves 51 in the framework 21 and flnallj.J emerging from the inner ends of the blades nearl the trailing edges 45 thereof and led across the drum I2. It will be readily understood that a pull on these cables 56 swinging the pressure feet 52 of the bell crank levers 50 downward will spring or iiip the free corners of the leaves 45 downward as shown in Figures 8 and 10 and the obstruction t'nus offered to the air ow beneath the blades will result in a great increase in the lift afforded by the blades in well known manner. At their inner ends the cables 56 are secured to bell crank operating levers 58 which are fulcrumed between bearing ears 53 near the center of the mounting plate 24 and each having a draw arm 68 disposed in line with its associated cable to which it is attached at 6l. These bell crank levers 58 are placed through4 slots 62 in the said plate 24 and the legs 63 drop down into the drum I2 where they are pivotally connected at 64 to push rods65 slidably mounted vertically through guides 66 in the bottom of the drum. Suiilcient play is provided in the connections 64' to allow the push rods when urged upwardly to swing the levers 58 and exert a pull on the cables 56 and flex the leaves 46 downward as described. Of course each cable 56 has its own operating lever 58 and separate push rods 65 are provided for each lever, the said push rods being evenly spacedand dropping down into contact with the upper end face of the bearing block I8 suppcrted in the turret I9. The lower ends of these push rods 65 carry rollers 61 as shown.

- A cam mechanism and operating means are provided for operation of the push rods 65 com- .prislng four hydraulic cylinders 68 secured up into the lower end of the bearing block I8 in alignment with the push rods and equally spaced fore and aft and laterally relative to the line of flight of the aeroplane. Pistons 69 are slidably mounted in the cylinders 68 and have their piston rods 10 extended upward through apertures 1I` in the cylinder ends and aligned bores 12 in the bearing blocks. Arouate cam heads 13 are rigidly attached to the upper ends of the piston rods and normally rest in enlarged sockets 14 at the upper ends of the bores 12 so that the rounded upper or working edges 15 of the cam heads normally stand ush with the upper end face of the bearing block 'I8. In this positinn the push rods 65 run free without any upward or downward movement but when any one of the cam heads 13 is projected upwardly the push rods as they run around over the rounded edges 15 `thereof will be rst raised and then dropped downward again resulting in a pull on the cables 56 and the exing of the leaves 46 downward during a sbort'portion of the travel of each blade 26, 26a, 26h and 2'6c. When the cam heads 13 drop downward into their sockets 14 the parts return to normal positionvof their own weight and under influence ofthe air pressure on the leaves 46 and the pull of the springs 53 on the bell crank pressure levers 58 as will be understood.

'I'he pistons 68 are urged upwardly as described by the pressure beneath of hydraulic fluid in the cylinders 68,'this fluid being carried separately to each cylinder by lines 16 through the lower -end caps 11 of the cylinders as shown. These lines 1'6 pass downwardly within the turret I8 and alongside one wall of the fuselage I I to four driver cylinders 18 arranged in equally spaced f relation about the control stick 18 and supported on a ring and bracket 8|. The said control stick 19 may be swung forwardly, rearwardly or to either side by its ball and socket mounting -82 and is connected by a spider 83 to the piston rods 84 of the pistons 85 in the cylinders 18 so that when the stick is moved by the pilot toward any cylinder the piston therein forced out the hydraulic uid under pressure and exerts an equal pressure in the corresponding cylinder 68 and moves the piston 68 therein an equal distance. This ofcourse makes it possible for the pilot by manipulation of the control stick 18 to move any of the cam heads 13 upward and so vary the side or place during the orbital rotation of the blades 26, 26a, 28h and 26o where the `lift of these blades is increased by flexing the leaves "downward as described.

Y This controllableand variable lift of the blades act to guide the aeroplane during flight as will 'now be described. Assuming thatthe aeroplane has risen horizontally from the ground to the desired height and the pilot desires to y forwardly in a horizontal line, he simply pushes the control stickk 18 in the proper direction (preferably forwardly but depending on the hookup of the cylinders 88 and 18) and the cam head 13 at the rear of the drive shaft I4 is.ele vated into the path of the push rods 65. Now as the blades 26, 26a, 28h and 26e rotate carried around by the drum I2 these push rods 65 as they pass over the raised cam head will be raised and then dropped downward as described hereinbefore. This results in the leaves 46 being exed downward each time a blade passes through the rear portion of its orbital path and the-lift or upward thrust of the rotor blades is thus increased at the rear tilting the aeroplane upwardly at the rear and gliding it forwardly. By nicely adjusting this lift by the position oi the control, stick 18 a balance can be obtained at which the aeroplane will glide forwardly at substantially even keel meanwhile being sustained in the air by the whirling blades. The same action may be employed to guide the aeroplane of! to the side or evento the rear by suitable manipulation of the stick 18 and by moving the "lift around the path of the blades as will be understood. In lieu of the leaves 46 at the outer ends of the blades 28, 28a, 2Gb and 26e swinging or hinged flaps or leaves 86 may be employed and pivotally mounted at 81 be arranged by a pull on the cables 66 to swing rearward and increase the chord of the blades at that point and hence increase the lift. The blades may be cut away at their trailing edges as shown at 88 and the leaves 88 then arranged to refill this space when the cables are pulled. Springs 88norma11y swing the leaves 86 forwardly clear of the space 88 as shown. It will be evident that to increase the lift of the blades the small amount necessary a very slight movement of the leaves 46 or 86 is needed and also that the increase in lift may be obtained in`a number of ways that is by varying the area of the blade, by varying the cross sectional shape or by a combination-of both and all are considered within the scope of my invention.

The mounting plate 24 and the parts mounted therein are enclosed by an inverted cup-shaped cover 88 which is screw threaded at 8I down over the upper margin of the wall 22 of the drum I2 and has openings 82 to clear the springs 28, 28a, 28b and 28o aswell as 'bearing sleeves 83 clearing the cables 66.

While I have herein set forth a certain preferred embodiment of my invention, it is understood that I may vary'A from the same in minor structural details, so as best to construct a practical device for the purpose intended, not departing from the spirit of the invention and within the scope of the appended claims.

I claim:

1. In a 4rotor for helicopters, a rotatable hub member, blades extended radially from the hub member, a bearing block beneath the hub member, cams arranged in thebearing block at spaced points around a circle having as its axis the axis of rotation of the hub member, a flap fastened by one margin to each blade, and control means whereby elevating any one of the said, cams will cause a flexing of the ap on each blade as it passes a point in radial alignment with thel raised cam to increase-the lift of the blade.

2. In a rotor for helicopters, a rotatable hub member, blades extended radially from the hub member, a bearing block beneath the hub member, cams arranged in the bearing block at spaced points around a circle havingas its axis the axis of rotation of the hub member, a flap fastened by one margin to each blade, and control means whereby elevating any one of the said cams will cause a exing of the ap o n each blade as it passes a point in radial augment with the raised cam to increase the lift of the blade, the

said control means including push rods depended with but capable of being exed downwardly to 5 increase the lift of the blade, means at the hub for periodically flexing the flap of each blade downwardly as it passes a point around the axis of the rotor, the said means comprising a plu,--

rality of cam located around the axis of the rotor, controlling means actuated by the cams and connected to the said aps, and remotely located means for selectively actuating the said cams.

WAL'I'ER W. RQ'I'HENHOEFER. 

